1. Technical Field of the Invention
The present invention relates generally to the releasable holding of cores and reels of paper, film, plastic, metals, fabrics or the like and more particularly to a holding device with at least two clamping segments, each of which can be fixed and changed in its radial position and moved on at least one profile.
2. Discussion of the Related Art
Holding devices are used to support sleeves in machines that process webs in such a manner that webs of paper film, metals, plastics, fabrics or the like that are wound on these sleeves, cores or the like can be unwound from these sleeves in order to be fed to a processing machine. The holding devices can also be used to rotatably support the cores or sleeves on which the webs coming from a processing machine can be wound.
During a processing operation, i.e., the winding or unwinding process, the reels located in the processing machine must be rotatably held as precisely centered as possible. However, at the end of each processing operation, it is necessary to remove the cores, sleeves or the like from the machine or even remove the reels of web-like material that is wound on them. Accordingly, it is required to release the cores from the holding devices carrying them. To accomplish this, one frequently resorts to so-called expansion clamping shafts or expansion clamping heads in which some components can be moved in such a manner, e.g., in the radial direction of the entire device, so that the cores can be either clamped or released from their interior and can be removed from the processing machine. The elements of the "clamping heads" that ca be moved in the radial direction for the purpose of fixing or releasing are often moved along tilted, thus requiring essentially wedge-shaped paths in order to be moved in this manner into either the clamping position or into the releasing position.
For example, a device for the releasable holding of cores is shown in U.S. Pat. No. 3,667,696. This device has several eccentrics arranged in such a manner that during a relative rotation between the essentially internal device and the clamping elements cause the clamping elements to be moved radially when the eccentric assigned to the respective clamping element is rotated. In addition, this device comprises at least two radially movable clamping segments or clamping elements which are mounted in such a manner on their carrier that they can be clamped into an extreme position. However, the sleeves, cores or the like that are held rotatably therein are often exposed to alternating forces. These forces can release the clamping of this device so that the clamping segments of the device move radially in an undesired manner, thereby undesirably loosening the clamped cores. In an attempt to prevent this problem, the end discs coupled with actuating ring device can be secured against turning by locking screws. However, this solution is complicated to manipulate and is therefore contrary to automatization of the clamping process.
Accordingly, it is an object of the present invention to prevent undesired loosening of the core clamping during automatic operation.
It is a further object of the present invention to prevent such loosening while achieving efficient clamping and releasing of the cores.
Other objects and advantages are apparent from the specification and drawings which follow.